Submitted to: Cereal Rusts and Mildews Conference European and Mediterranean Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/6/1996
Publication Date: N/A
Technical Abstract: Resistance to oat crown rust in the USA is based on race specific resistance genes from Avena sterilis, from Israel and North Africa. A. sativa is not grown commercially in Israel, so virulence diversity from wild populations of Puccinia coronata in Israel can be compared with that of P. coronata on cultivated oats in the USA using differential lines with resistance genes from A sterilis. Isolates of P. coronata from A. sterilis and A. barbata throughout Israel in 1991-1994 and from A. sativa in the USA in 1990-1994 were tested for virulence on 26 oat lines with named resistance genes from A sterilis. Six of the named genes, Pc38, Pc39, Pc58, Pc59, Pc60, and Pc61, were used extensively in oat cultivars in the USA and 9 others were used in components of the Iowa multiline cultivars. Nearly all USA isolates had some unnecessary virulence, but virulence to most differentials was more common in Israel than in the USA. Only the line with Pc68 was resistant to all isolates from Israel. Pc68, which is from A. sterilis from Algeria, also was resistant to 99% of isolates from the midwestern USA. Average numbers of differentials attacked by isolates were similar for different regions of Israel except that isolates from the Negev and Lower Galilee were virulent on fewer (16-17) of the 36 differentials than isolates from other regions (average 18-21). Isolates from Texas in the USA in 1990 averaged virulence on 10 of 36 differentials; isolates from the Midwest averaged virulence on 11.